HELP SAFE MODE DOES NOT WORK

my display driver messed up my desktop and im trying to go into safe mode to fix it but safe mode wont show up. IM running windows vista.. i keep tapping F8 when it boots and nothing shows up. I also tried holding F8 no luck either..Since my display driver is messed up could it not show the writing for safe mode. Becauce when i tap f8 or hold it it seems to give me a longer black screen then usually