XPS 410 with (i think) a BIOS virus, solutions??

What are the stats of the computer now?

If the computer had its BIOS jacked up by a virus for a second time you may want to first tell her to quit downloading and running viruses on her computer.

If she is downloading music or movies or any kind of pirated software, stop her.

No matter what you spend your money on now she will just keep breaking it if she keeps doing this stuff and doesn't stop.

If she isn't going to stop, you might as well just buy her the oldest cheapest suckiest board that will work for her computer because its probably going to be dead soon anyway and you don't want to spend on high quality stuff in those conditions.

There is no solving a corrupted BIOS most of the time. Some portion of the time if you take the battery out for 30 min it will force the BIOS to recreate a master configuration table and that could fix the problem.

However, if you never get that far because the BIOS is really messed up, then usually the motherboard will double as a paperweight from then on.

Getting her on Ubuntu wouldn't be the worst idea, then at least if she does stupid things its less likely to harm her, but Linux is not reliable protection against human errors.

Most people get viruses because they lower their own security stance, and that is doable no matter what OS you use.

At the very least if you are going to get rid of her whole PC, you can try to test some of her old parts in the new PC to see if they are still good and if they are then ebay them to recover some of the costs.

most of the viruses that look like cmos virus are ones that are in the master boot of the hard drive or make a new master boot and a format wont kill them. I would do an fdisk/mbr and then an fdisk and remove all the partions on the hard drive. I would then use the dell recovery cd to put the factory image onto the pc. I would then uninstall the old anti virus that on the image and use avg/avast or mse and do a full drive scan.