PC Mobo taking a dump on my chest.

Dr. Phibbs McAthey

So, my trusty PC, the first one I ever built (I've since built about 8, much better, pcs for friends and family), has decided it's time to go. It all started last summer, when a lightning strike fried the network adapter on the motherboard. No big, everything else seemed to be working fine, I just got a cheap PCI adapter and went on my merry way.
Ever since then, though, I've noticed some odd things on startup: (Spoilered for long)

1)I should preface this by saying that I have two hard drives, an IDE 120gb by Western Digital if I remember correctly, and a SATA 200gb WD. My windows install and most programs I use on a regular basis are on the SATA drive. This actually happened every once in a while before the strike, but sometimes when I shut down or restart, the bios would think that my primary drive was the IDE drive and not be able to boot Windows. Because it wasn't on there, being used mostly for backup. No big, I just change the settings back to the SATA drive being my primary drive in the BIOS. Lately, however, it's literally every time I restart the thing.
2)Sometimes I get stuck in an infinite reboot loop. Sometimes it will get as far as getting to my desktop, but then the whole thing will restart. Once it starts, the time it takes to reboot itself gets shorter and shorter, until I'm barely making it past the BIOS splash screen.
3)My Pioneer DVD-R drive oftentimes doesn't like to read the disks that I put in it. I plan on remedying this by smashing the fuck out of it Office Space style (old reference, I'm sorry) and buying a different branded one. This was the first of 3 pioneer DVD-r drives I've put in computers, and all of them as far as I know are somewhat fucked.
4)Sometimes when the bios isn't infinitely rebooting or knocking the primary drive back to my IDE drive, it hangs at the startup screen. When or if it decides it's done hanging, I get a message saying 'overclock failed, f1 to enter setup or f2 to load default values and continue'. I usually hit f2 because that seems to be pretty stable once it's up and running.
5)Every once in a great while my monitor won't detect the video card until I reboot the damn thing.

Now, more Windows-based (or hard drive based, not sure yet) problems are surfacing, such as not allowing me to open more than one web browser window at once. Well, really that's the only one, currently, that I can remember.

So, I've deduced that something's fucked with my mobo. A friend told me to try and get the bios battery replaced and/or flash the bios, and see if that made anything better.
Failing that, I'm going to have to beg and plead with my wife to let me spend some of our tax rebate money on new parts.
So my request here, I guess, is a partial build of new mobo/CPU/ram for less than $500. Hard drives are cheap enough now that price isn't a really big concern, and I'm pretty sure my power supply is fine because A)I love it, and B)Everyone I know with blown power supplies have had them basically explode or stop powering the thing altogether, and mine has done neither. My optical drives are uber cheap to replace now (except, does anyone know if getting them with SATA inputs is any more expensive? I'm fucking tired of IDE ribbons). Yeah, pretty much all I'm in dire need of is mobo/cpu/ram.

Edit: Flashed the BIOS (It's an ASUS P5RD2-VM if anyone's interested) and it seems to have fixed my problems for now. Gave me a bad CMOS checksum once and tried to boot from my IDE drive but after reconfiguring it, it booted right to windows with zero problems.
Still, I don't know how long this will last and my above request still stands