Hmmm... some of you say to do it as a favor because she's family... yet you tell me not to help her when she needs it?  That doesn't make sense.
I don't mind helping her... I did that before anyway with her crappy HP, and my uncle's crappy Sony.  (yes, Sony is crappy... I replaced the power supply in it once, the floppy drive once, and the DVD burner twice)
I had the computer set up for her to see and use and she was ecstatic.  I thought she was going to cry over the LCD, lol.  I showed her some pretty equally equipped Dell's in the range of $1200-$1600... and some pretty equally equipped HP's without an LCD in the range of $700-1200.  Actually... here's something I printed out for her to tell her what exactly she has...
Case - Antec Solution Series SLK1600 (Mini Tower w/ 300 watt power supply and 2 Front USB ports)
Motherboard - Epox 8RGA (nForce2 chipset with integrated GeForce4 MX video card and integrated SoundStorm soundcard capable of 5.1 Digital Dolby Surround sound)
Processor (CPU) - AMD Athlon XP2500 (333 Mhz bus, 512k L2 cache, 1833 Mhz with heatsink and fan included)
CD Drive - Lite-On DVD/CDRW Combo drive (reads DVD?s at 16X, writes CD?s at 48X, rewrites CD?s at 24X, reads CD?s at 48X)
Floppy Drive - Samsung 1.44 MB 3.5 inch floppy drive
Case Fan - 1 additional 80 mm Front Case Fan
Hard Drive (HDD) - Western Digital Caviar Special Edition 120 GB (7200 RPM, 8 MB cache)
Memory (RAM) - Kingston Value RAM, 512 MB (PC2700 333 Mhz CAS 2.5)
Network Card (NIC) - Siemens PCI 10/100 Ethernet Card
Monitor - Envision EN-7100 Si (17 inch LCD, 1280x1024 @ 60 Hz native resolution? 400:1 Contrast Ratio? 250 cd/m2? 30 ms typical response time? 45 watt power consumption MAXIMUM)
Anyhow... she asked me how much she owed me... I told her she didn't have to pay me anything, but if she wanted to then she could decide.  The computer with the 17 inch LCD ended up costing $815... she wrote me a check for an even $1,000.  I told her that was too much, and she told me if she had bought one somewhere else she would have ended up paying even more, so in her eyes, she's still getting a great deal.  So anyway... she payed me $185 for building it... and she said she knows some people who might want one built too... now them, I would tell I won't provide "tech support"  ... but for family, I do anyway, so I have no problem continuing to do that. 
*EDIT*  BTW... thanks for the opinions =)  Seems as though a lot of you think this was a bad idea... but she's very happy with it, and I'm happy to help her out.