Did you just stumble upon a download or a file on your computer that has a digital signature from PC Fixer Tools LP? Some of the security products refers to the detected files as not-a-virus:RiskTool.Win32.SysTweaker.gen and W32/Trojan.QPGF-7890. The detection rate for the PC Fixer Tools LP files collected here is 22%. Please read on for more details.
You'll probably notice PC Fixer Tools LP when clicking to run the file. The publisher name is then displayed as the "Verified publisher" in the UAC dialog as the screenshot shows:

You can view the additional details from the PC Fixer Tools LP digital signature with the following procedure:
Here's a screengrab of a file digitally signed by PC Fixer Tools LP:

As you can see in the screenshot above, Windows reports that "This digital signature is OK". This implies that the file has been published by PC Fixer Tools LP and that no one has tampered with the file.
If you click the View Certificate button shown in the screenshot above, you can see all the details of the certificate, such as when it was issued, who issued the certificate, how long it is valid, and so on. You can also view the address for PC Fixer Tools LP, such as the street name, city and country.
COMODO RSA Code Signing CA has issued the PC Fixer Tools LP certificates. You can also see the details of the issuer by clicking the View Certificate button shown in the screenshot above.
The following are the PC Fixer Tools LP files I've gathered, thanks to the FreeFixer users.
| Detection Ratio | File Name |
|---|---|
| 14/65 | ggamesst.exe |
Here's the detection names for the PC Fixer Tools LP files. I've grouped the detection names by each scanner engine. Thanks to VirusTotal for the scan results.
| Scanner | Detection Names |
|---|---|
| CAT-QuickHeal | Trojan.Speedchecker |
| Cyren | W32/Trojan.QPGF-7890 |
| DrWeb | Program.Unwanted.3156 |
| Fortinet | Riskware/SysTweaker |
| Kaspersky | not-a-virus:RiskTool.Win32.SysTweaker.gen |
| MAX | malware (ai score=94) |
| McAfee | Artemis!504649344933 |
| McAfee-GW-Edition | Artemis |
| Microsoft | PUA:Win32/SpeedChecker |
| Panda | PUP/PCCleaner |
| Qihoo-360 | Win32/Virus.RiskTool.f9e |
| Sophos | Generic PUA CC (PUA) |
| TrendMicro-HouseCall | TROJ_GEN.R002H07BR19 |
| ZoneAlarm | not-a-virus:RiskTool.Win32.SysTweaker.gen |
The detection percentage is based on the fact that I have gathered 65 scan reports for the PC Fixer Tools LP files. 14 of these scan results came up with some sort of detection. You can view the full details of the scan reports by examining the files listed above.
The analysis has been done on certificates with the following serial numbers: