Application Problems, Please Help!

Well, IDM hasn't worked for a while now, it's like my registry keys are messed up. But, here's my problem, I was reading online and if I typed ''bcdedit..something..something..something'' into the command prompt, it'll stop Windows Vista 64-bit to not require signed drivers. Well, I needed to do that to use RivaTuner to overclock my graphics card, then, RivaTuner didn't even work, so I did that all for nothing. I tried disabling the 64-bit signed drivers w/ every way that was given, by using VistaBootPro or typing what ever I had to type into the command prompt, nothing worked. So, I restarted my computer after I had deleted RivaTuner and VistaBootPro and then FRAPS just popped up and said it couldn't respond or there's a problem and Windows is checking for a solution, since FRAPS starts w/ Windows. Also, what ever I did messed up my Norton Anti-Virus, it says all I have to do is re-install and it should work. But now, my 2nd download manager doesn't work (DAP, DOWNLOAD ACCELERATOR PLUS), it keeps saying Windows has encountered a prioblem or something like that and then just closes. I've tried using System Restore from before I did all of that and then I tried to restart my computer (of course) about three to four times and I even shut off my computer for an hour or so, still, nothing worked. So then, I tried to un-install DAP, that worked, but then I tried to re-install it and it still didn't work, the same w/ FRAPS, I haven't tested Norton yet, but DAP was the free version, but I still liked it and I don't know of any other download managers better than IDM or DAP. So, what can I do about this problem?Thanks for the help, if I get replies...