RECOMMENDED ORDER FOR HELPING* SECURE YOUR PC
* While this may help lock your system down against current spyware and trojans, new ones are being developed all the time - secure what you can now, and remain vigilant !
** Please note - this is a revised list due to the spreading menace of "rootkits" **
1) Scan your machine with the Blacklight rootkit detection utility
2) Scan your PC with Sysclean from Trend - especially if you use Nortons or AVG !
3) A firewall
4) A virus checker
5) Spybot Search & Destroy
6) SpywareBlaster
7) CWShredder
Due to the prevalence of some more malicious malware now, I would also consider running these, even if you have no outward signs of problems yet - reboots may be required, and one of them takes a good few minutes the first time you reboot, so don't panic :-}
7a) Vundofix
7b) Fixwareout
1,2,3,4,6,7 (and 8 below) are all available via links from the "Other spyware utilities / info" page
5 is available from the "Spybot Search & Destroy Help" page
If these doesn't resolve any existing problems try...
8) HijackThis! * WARNING * - deleting the wrong things can prevent your system from booting up
If you use HijackThis! be sure to Google for help on any programs you don`t recognise rather than just deleting them - several forums / message boards are available that might be able to give more in-depth help with the results.
If you still see nothing obvious or untoward, its possible you have a desktop hijacker, in which case try SmitRem from the "Other spyware utilities / info" page.
Notes:
I *strongly* recommend NOT using IE (Internet Explorer) - it is dangerously full of security holes. Use Firefox or Opera instead.
More FAKE spyware detectors / cleaners are offered for sale than legitimate ones - more info on what is fake / legitimate can be found here
I don't normally recommend commercial applications for dealing with spyware, but Pest Patrol might be worth a go if this is all too daunting for you (i've seen it in action and been impressed) !