I uninstalled and re-installed both the game and the STEAM 02.03.2010 trainer, then ran both as administrator and it still crashes the game whenever I try to do anything after hitting F1 to activate the trainer. Could my save file be corrupted or something?
Possibly, more likely an anti-virus problem
Extract trainer and make sure trainer/launcher/editor is in a folder excluded from virus scans. Empty quarantine folder if needed or set anything trainer related (paths and EXE's) to ALLOW. Disable any Live/Active/Real-Time tools which may trigger false positives in security software which may terminate the game/trainer when it's activated or options used.
C:\Users\USERNAMEHERE\Cheathappens
may need to be added to exclusions as well. Run trainer as admin, read the instructions and try again.
Anti-virus help page. Link
since it's older trainer other exclusions may be needed
e.g.
C:\Users\USERNAMEHERE\AppData\Roaming\Cheat Happens\0x90\
C:\Users\USERNAMEHERE\AppData\Local\Temp
C:\Users\USERNAMEHERE\Cheathappens\Work
C:\Users\USERNAMEHERE\Cheathappens
C:\Users\USERNAMEHERE\AppData\Local\Temp\CH_Temp.tmp
C:\Users\USERNAMEHERE\AppData\Local\Temp\~Mnn133.tmp
C:\Users\USERNAMEHERE\AppData\Local\Temp\~CheathappensTrainer.tmp
C:\Users\USERNAMEHERE\AppData\Local\Temp\CH.dll