HELP ! Malware problem?

Help, my malware problem has gone from bad to worse, and now after booting up, once the windows xp logo is over all I get is a black screen! In every mode of booting, via the F8 key, I've tried them all and get black! The background is a laptop (my daughter's) with at least 23 trojan, virus, etc. programs as identified by a program called "A-Squared" free version, however I got ahead of my self and tried to delete some of the identified items and bam...black, now what?:confused