Well, I don't know why my first post only shows the link to the clean install because I posted a lot more information than that. I guess the squirrels running the cages around here went on break again.
I too said to highlight the existing partition and then click next, and if that doesn't work you can try the following.
Try this.
When you get to the Custom Install screen, hit Shift + F10, this will bring up the Command Prompt.
Then type this:
diskpart
Then type:
list disk
It will show you a list of the disk connected to your computer. In your case it should only show Disk 0. If this is correct type this:
select disk 0
Then type:
clean
Then from the Custom Install select New and leave it to use the entire volume. It will warn you that it needs to make a System Reserved partition, let it. Windows should install.
And if you still get no love, I'd try unplugging the power cable from the wall, removing the CMOS battery from the motherboard for a few minutes, put it all back, go into the bios and select the option for optimal default or default setup settings, save and then try again.
If you still get no love then I'd try running checking the disk for problems.
Insert the original Windows disc.
Restart your PC and boot from the disc.
Click Repair your computer.
Choose the operating system from the list.
Click Next.
Choose Command Prompt.
When it opens, type the command: chkdsk /f /r.
Press Enter.