Would System Restore get rid of Trojan.Agent/Gen-Dropper?

My first question is whether to go forward or back: must I proceed with full-scale malware removal to be sure of getting clear of a recent Trojan, or can I just use the System Restore to roll back to a few days before it turned up, and then toggle the System Restore?

My second question is whether to let Windows Live clean up 225 entries in my Registry that it doesn't like. (See below.)

I have a PC that runs Vista; it has been clean of any malware as long as I can recall. I run all your recommended anti-malware, I install Windows critical updates promptly, and I've updated everything the FileHippo Update Checker found.

On Saturday, 2 days ago, SuperAntiSpyware found something it called Trojan.Agent/Gen-Dropper. The log showed it to be in
C:\USERS\JANET AND THOM\APPDATA\LOCAL\MICROSOFT\WINDOWS\TEMPORARY INTERNET FILES\CONTENT.IE5\K6T01FZX\FIREFOX%20SETUP%203.6.10[1].EXE.
I quarantined and removed it. Both SAS and MB came up clean in full system scans in safe mode. Spybot came up with 3 other things looking like tracking cookies, which I removed.

Yesterday, Sunday, I used CCleaner to permanently delete all the temporary Internet files. I also went to my neighbor's clean computer and changed my banking passwords!

Then yesterday I got messages in the tray that the Security Center could not be started, and that the Intel Rapid Storage Technology was not on. Today the tray sent up a message that there was a problem that I should click here to fix. The icon was called "Problem Reports and Solutions." I went to Search from the Start menu, found, and opened up the Problem Reports and Solutions window. It showed a message to go to the Symantec website to fix a problem with Norton 2009 or 360. When I went to Norton it told me I had to run Live Update. But on my computer's Norton it says that Live Update ran successfully a few minutes ago.

I downloaded and ran the Windows Live full service scan for Windows Vista and Windows 7 just now, and it did not find any malware but it tells me I have 225 invalid registry entries that it wants to fix. Wow. After running CCleaner every day?

So will someone please give me your best advice on what my next move should be. Would a simple System Restore work, or am I dreaming?

thanks much,
Janet

 

Most valuable information. Thank you, chaslang. That answers my questions exactly. I may be back with logs, but right now I'm going to hold off and see how it runs. Thank you, thank you.
cheers,
Janet