I would reinstall it and turn off its security guard and then it would not be using too many resources and just use it as a on demand scanner!
You already have MSAS so you can use that for real time protection!
You should also consider these tools!
here's some free tools to keep you from getting infected in the future.
to stop reinfection get these two tools, spywareguard and spywareblaster
from
get the hosts file from here.
put it into :
Windows XP = C:\WINDOWS\SYSTEM32\DRIVERS\ETC
Windows 2K = C:\WINNT\SYSTEM32\DRIVERS\ETC
Win 98\ME = C:\WINDOWS
ie-spyad.Puts over 5000 sites in your restricted zone so you'll be protected
when you visit innocent-looking sites that aren't actually innocent at all.
Use spybot's immunize button and use spywareblaster' enable
protection once you update it. you can put spybot's hosts file into
your own and lock it.
I would also suggest switching to Mozilla's firefox browser, it's safer, has
a built in pop up blocker, blocks cookies and adds. Mozilla Thunderbird is also a good
e-mail client.
Another good and free browser is Opera!
Read here to see how to tighten your security:
A good overall guide for firewalls, anti-virus, and anti-trojans as well as
regular spyware cleaners.
Member of ASAP Alliance of Security Analysis Professionals
under the name khazars