AVG is an anti-virus program, you can have malwarebytes and its great. But malwarebytes is a malware removal tool, its
not an anti-virus program.
I don't see anything wrong with AVG on Vista. It's what I use on one of my laptops and I have found that AVG runs minimally and nicely and it does a fine job as an A/V.
Vista is somewhat of an odd one. I sat down one day and messed with trying to get that RAM usage down, to no avail. Its just how Vista runs! Though, there are things I've done to get the system to run faster like stopping and then disabling (via services.msc) superfetch, wireless, java starters, ms office software extras, bonjour, all apple junk, messenger, remote access, windows search. I also uninstalled unneeded/unwanted programs, cleaned the startups/system tabs in msconfig. Then ran Malwarebytes, SUPER AntiSpyware, and ran CCleaner and defragmented the HDD with Defraggler (both from Piriform) and ran chkdsk. (I did not do it in that specific order. I am also not recommend that you do all of this either. This is just an overview of what I've done.)
Another step I take with my machines is that I usually only put them in standby or hibernate when I am going to be away from them for awhile. I don't shut them down all the time, it takes too long to restart Vista! I
typically only restart once a week.
We can definitely check to make sure there isn't anything malicious lurking in your system taking up valuable resources:
-----
Please download Malwarebytes' Anti-Malware
HERE or
HERE and save it to your desktop.
Please create a HijackThis log by doing the following:
Download the HijackThis installer from
HERE
Run the installer and choose
Install, indicating that you accept the licence agreement. The installer will place a shortcut on your desktop and launch HijackThis.
Click
Do a system scan and save a logfile
Most of what HijackThis lists will be harmless or even essential, don't fix anything yet.
Post the log file that HijackThis produces along with the Malwarebytes Anti-Malware log; and tell us how the system is running, any better?