FPS drop in BF2

[[NRNS]Xenalite]

Normally I have 60-100 FPS on highest settings in BF2. Then without any change, one day I have max 25 FPS on lowest settings. I reinstalled the game, the OS, drivers everything and it's still not back to old state... Any clues?

[[NRNS]Suraj]

Can you provide your system spec?
is it stable at 25 FPS or drops in between game?
Possible causes
1. Temp goes high, n  temp software tries to step in (majorly seen in laptops)
2. antivirus or firewall
3. conflicting application that you have recently installed  (more seen)
4. Read/write operation delay (frequent cause).
5. possibility of demand paging
Let me know the specs

[[NRNS]Xenalite]

Do you happen to know any good system performance loggers that would help me identify the problem?
Do you think that where I installed my game matters? I had it installed on an SSD before (and it went bonkers while on SSD), now I installed it on an old HDD, still the same problem.