Linpus is a little lacking on information on their website, but it is based on Fedora, so...
If the partition that you can't delete is at the begining of the drive, with the MBR previously occupied by a ext3 partition to boot, then this is likely the issue.
What hard drive make and model do you have? You can use the manufacturer's utility to zero write the drive and make one single fat32 partition, then install Windows.
The issue is that generally you can't just try and delete the partition(s) easily with a utility that doesn't recognize all Linux partition types then try to install Windows on the drive, leaving the errant partition is on the drive. Many folks make the mistake to think that this will work, just deleting the apparent Linux partition, then installing Windows.
But, humbll is correct, what utilities do you have available to erase the apparent Linux partition and make one fat 32 partition. I suggest posting your information here so that users can respond and walk you through a solution.
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"I love it when a plan comes together." - Hannibal Smith