My new HDD SMART reports 963 days power-on time

I have a core i7 desktop, and a core i3 laptop, both are HP, and both are out for service, the optical drive on my laptop says "power calibration error", and the desktop can't detect the hard drive.
HP will take 10 days to return both.
And here's the problem, i'm a computer addict, and i really cannot go 10 days without a home computer. So I took out my11 years old desktop from the garage, and powered it on. And the thing said "disk boot failure" (after CMOS checksum error-defaults loaded), with loud clicking sounds coming from the hard drive.
I then went to this local computer store, and got myself a hard drive. The tech at the shop told me they no longer make PATA hard drives, and the only option i have is to get a second hand refurbished hard drive, because this dinosaur won't accept SATAs..
I got this second hand hard drive for US$48, and the computer shop provided a 6 months replacement warranty.
The first thing i did (after installing XP) was check the HDD with "Acronis drive monitor". Everything looks cool as of now, and i'm typing this on this 11 years old desktop. But SMART attribute "Power on time" reads 963days! Is this worth the money? or shall i return this and get myself a new cheap Chinese netbook for these 10 days? I won't be using this desktop once i get my other computers back from HP service.but if i get a netbook, i'd be able to carry it to my classes, and save myself from carrying a 5KG 17 inch laptop.
What do you suggest? Get the refurbished HDD? or Get a new netbook? Every other attribute except the power on time reads 100% ok, and acronis drive monitor reads "Disk health 100%". thanks