Strange CMOS/Boot Issue

I'm building a computer for my girlfriend and I decided to go the small form factor route, but I'm having issues with boot up. My components are as follows:

Shuttle Sn41G2V2
Athlon XP 2600+ (333 FSB, 512K L2 Cache)
512 MB OCZ PC2700 (2x dimms, 2-2-2-5 CAS latency)

Due to my problems I haven't hooked anything else up yet.

At first I couldn't get the computer to post at all. The monitor wouldn't wake up. I removed and re-inserted the battery for the motherboard (a shuttle fn41v3, forgot to mentionthat) and it didn't do anything. I'm sure everything was connected properly and I got no post-error beeps or anything (though i'm not sure if the motherboard supports it, it doesn't say in the manual or on shuttle's web site). I was finally able to get it to post by switching the clear CMOS jumper, turning it on, turning it off, switching it back, and turning it on again. The fan starts up, cuts out for a second, and then it posts. it says "CMOS checksum error - defaults loaded, warning! now system is in safe mode, please re-setting CPU or memory ratio/frequency in the cmos setup." No matter what I do when I enter the bios setup, once i exit it won't post again unless i reset the clear-cmos jumper. Even resetting it won't post unless i do that. Hitting F1 does nothing.

I'm really confused. Please help.

You may change CMOS battery. Probably Bios itself may be corrupted, but you had better not do many things upon this if it's new mobo. Give it back to the vendor.