...well you can either delete the panda files, or exclude them from scanning in avast's options
(I don't have avast on this here PC so can't tell you the exact way to do it right now, but I guess if you're so proficient you can read/see help, faq's & Docu.. )
[EDIT]
same applies for "Uninstall", but if I understand you correctly
-> ControlPanel -> Add/Remove Programs -> avast ... would be a likely choice..)
If you mean PANDA_OnlineScan-Uninstal -> look in Downloaded.Program.Files (OBJECTS in IE-Options)
[/EDIT]
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the reason for my questions about trojan-gen & onlinescanners is that:
- Trojan-Gen is a generic detection/name which comprises probably Dozens to hundreds different trojan-species/variants, and
- from your info it is not clear whether yours is a false alarm or not..
- or if it's just located in protected areas and thus can't be removed easily.. (_RESTORE .. ?)
- Trojan-Gen has in the past been known to detect stuff like fully-fledged Backdoors, but if you want to exclude that one from scanning -> your choice
--> I just wanted to help..