Get a partition virus or a bad sector in the wrong spot and you're $$$$ed.

Two drives are much better than one, but if you really can't afford one, then backup to CD.

Yep Chrome, your right about 2 drives as the dux solution [I'd like 3 ....one for the OS and programs, one for the paging file [swap file] and one for important data and other files.
Alternatively a small USB [1G to 4G] keychain drive is a cheap handy alternative as a data backup [better than disks] and will backup a fair amount of data.

Failing the above, a partition for the OS and one for files [and one for programs if you like] is a pretty good alternative for the average Joe. Mostly it is the OS that crashes and the partition can be simply re-formated and the OS re-installed.

Superantispyware
 

I have been using the freeware edition for a year or more,it finds,

"Not just the easy ones" - updates once or twice a day.

www.superantispyware.com/

Two weeks ago I installed and ran it on someone else's machine and it
found 133 Trojans and various other charmers.

HTH,

Regards.

Beware of bulletproof software, it is full of spyware and pretends to be an antispyware application.

The program posted above is a good one, as is a-squared.

It's best to have more than one anti-spyware program.
Spywareblaster is the only freeware program offering real-time protection and Ad-aware, Spybot and Ewido 4 to back Spywareblaster up are good options.

Probably overkill if neither IE or Firefox browsers are used.