I had endless problems like that with Win95, mostly IRQ conflicts. The problem is that Win95 never should have been released. It wasn't finished until the version they called Win98SE. Every time I installed a new card or piece of hardware the whole system would start experiencing serial crashes.
My solution: Win98SE, a vastly more stable OS, and disable PnP in the BIOS setup, allowing (or forcing) BIOS to assign resources. End of problems- even through processor, memory, HD and even mobo upgrades. System is finally so flawlessly stable that I haven't upgraded the OS. (I'll be damned before I'll give any more $$ to MS! They should pay me for all the grief and expense of wrestling with their faulty products.)
With Win95 I could never get scanner/printer/digicam/soundcard/network card working all at once; sometimes no more than 1 or 2 of these devices at a time, sometimes nohing worked. Get ahold of a Win98SE disk, run fdisk.exe and reinstall your OS and drivers. It sounds scary but you won't regret it.