MusicLaw

To make certain that you are dealing with a clean slate, download and install the latest version of Helix Edit 2.51. Follow the installation steps and this will handle installing the latest Helix firmware 2.50. Then after it is complete, do another full Factory Reset (PowerOn + FS 7+ FS 8) to rebuild the Presets! If you have any custom Presets, be sure to Backup these first!
 
The type of pickups (and electronics, on your guitar or in your signal chain before Helix, if any), can have a significant affect on your Tone. 
 
Other than the above, I too would be suspect as to the type of headphones you are using with the Helix. 

Digital Igloo (Online Handle of Line 6's Helix Senior Product Manager), posted a few months ago that they are looking into this issue. There was no promise that this capability would be implemented, nor was there any timeline indicated. I would not expect this to appear in version 2.5 firmware (anticipated to be released this coming week). 

Short answer is "No." Line 6 does not offer a download version of HX Edit for Win XP.

Your DXR10 should be fine! Best thing to do is simply use it as normal.
 
In case you did not already know, the Yamaha has built in Signal Limiter and Power Protection Systems. These remain active regardless if you may have disabled the LED Indicator. See your Yamaha DXR User Guide (also available as a PDF), Pages: 7, 8 and 12.

Download the Helix User Manual 2.0 (Rev D) PDF from the Helix Line 6 Support Area (if the version on your USB stick is older).

This sort of a repeating momentary drop out, seems like it may be an RFI (Radio Frequency Interference) problem, possibly from what is known as signal capture which can occur if there is another nearby strong signal.
 
When you power on the G10 system with the transmitter in the receiver base unit (or a Spider V amp) it scans for a clear channel (amongst the 14 it has available to operate on). It will do this each time you power on the base unit with the transmitter connected. If your location has other strong nearby signals (WiFi Router, Microwave, Wireless house phone, other WiFi or wireless devices, etc.) the G10 will bypass any of it's 14 channels that are noisy or busy to select a clean channel. However, if the other signal sources are not active when you first power on your G10 system, those possible interfering signals will not be detected by the G10. Thus, the channel the G10 uses will be the first clear one it finds. This may be close to the offending interfering sources -- when they are active -- causing the momentary dropouts.
 
The best method would be to begin with all of those other potential signal sources in full operation. Enable the or cause them to be in operation before you poweron and insert the G10's transmitter into the base to allow the G10 to see the offending signals, thus selecting another clear channel to use.
 
Keep in mind that once the G10 finds a clear channel to use, the next time you reseat it back into the base, the process will reset back to square one. If you discover this, you may want to get the dedicated G10 USB charging cable to avoid having to reseat the G10 back to the base to recharge it, or, simply repeat the channel selection process with the other signals in full operation. This same sequence would be the case, for example, if another band member also had a G10 and you each wanted your G10 to operate on a different channel. You would have to start one and begin using it. The next unit, while it is in the powered base, would then seense the first G10's transmission on the first channel, and the second G10 system would select another channel.
 
If none of this works, contact Line 6 for them to assist.
 
There is no method to set and lock the G10 for a desired channel using solely the base and receiver. I believe, I read that manual G10 channel selection is available via the Spider V Amps menus when the G10 is used with those amps.
 
Hope this helps.

I've often connect my Helix to my Yamaha THR10C Amp and it sounds fantastic! The Yamaha THR10C is certainly not going to get loud. However, positioned near field it's Stereo FRFR does a great job on a desk, cocktail table, end table, etc.
 
Route the Helix to the Yamaha's AuxIn and the signal bypasses all the DSP in the Yamaha, and the batteries last hours longer! Route the signal to the Yamaha's Instrument In, and it runs through the Yamaha's DSP.
 
I also A/B'd the Yamaha against a set of JBL LSR305 monitors (each fed from the Helix). I was amazed at how well the Yamaha compared! Only at higher SPLs did the LSR305 clearly prevail, and, of course, the JBL's had a fuller bottom end.
 
Helix to Yamaha THR10c is certainly not a conventional configuration, but I had the amp anyway, and was delighted how well it worked as a battery powered stereo FRFR monitor for the Helix.

Thanks guys!
Through decades of technology business and legal affairs, audio engineering, and computer IT experience, I've grown accustomed to the plain reality that with every new iteration of a product firmware upgrade there are quite likely to be issues. It is always a best approach to get input from those whom have already plowed the road!
A new PC is in the works, for early 2017, if not sooner. Until then this HELIX will strictly be a stand alone device.
 
It is truly unfortunate that for these sorts of firmware update houskeeping chores, Line 6 has not yet provided Android support for the HELIX. The several Android Tablets I currently use are quite adept at USB OTG chores for a panoply of other devices.

An additional concensus of replies over on TGP reiterate that the cap is for the Variax jack. I'll fish it out of the recessed treadle adjustment hole and cap the Variax jack.

Just received the new G10 Relay USB Charging cable from Amazon this morning and used it to top charge my G10 Transmitter from a USB battery pack.
 
This has already proven to be a convenient alternative charging method, as there's no need to return the Transmitter to the Base unit which is located with the amps across the room.
 
The cable is well constructed from durable cabling and has moulded strain reliefs at both ends. The G10 Transmitter seats very securely in the 1/4" female jack. After reaching full charge (Transmitter's LED Steady Green) unplugging the cable from the battery pack causes the Transmitter (still attached to the cable), to enter Sleep Mode 4 minutes later. Leaving the transmitter connected to the cable, also will make both items far less likely to be misplaced.
 
The cable assembly measures 44".