Your OS partition is definitely too small. In fact, the entire HDD is really too small for practical use. Even if you could cram your OS and all your programs onto a single 24.8 GB partition, the OS would be strangling for room for temp files, etc. I would use just the 80 GB alone for your boot drive (my old XP desktop has a 100 GB partition for the boot drive) and add a second, larger one for your data.
If you can get by with only 80 GB for storing your data (I realize not everyone is data greedy like I am), an even better option would be to add a 64 or 128 GB SSD for your boot drive.
If getting another drive isn't feasable, the easiest fix would be to use one partition for your OS, the second for your programs, and the third for your data. Better would be to delete one of the partitions and expand the boot partition to the remaining space on the HDD. I personally feel 64 GB is a bare minimum for a boot partition but, if you don't run too many programs, you could do fine on a 49-50 GB partition.