First I'm going to assume some things. The Biostar board requires DDR memory. I assume that you are not taking the memory from your old HP Pavilion and putting it into the new board (it won't fit). If you were, you'll need a board that takes SDRAM not DDR RAM. It looks like you also need integrated graphics, too. So, assuming that, here goes...
First, Tiger Direct is the devil incarnate. They sell crap and treat you like crap. You may not get immediately ripped off, but often you will end up waiting weeks (or even months) for your stuff to be restocked. They won't tell you it's out of stock unless you ask them directly. If you ask them when it will be in, they'll tell you about 5-7 days, but they're usually lying. Their shipping is exorbitant, too. I used them a few years ago, but after I realized there were better alternatives (pretty much anyone), I won't even consider them.
Secondly, the system. Here's what I would do if I had about $110 to build the foundation of a new computer. Try www.newegg.com.
Get an AMD AThlon XP 2100+ processor and make sure it is the retail box, not the OEM because you need the Heat Sink Fan. That's $72, no shipping charge.
Check the refurbished AMD motherboards. For you, I recommend the MSI K7N2G-L it's $59, again no shipping. Here I go with the refurb thing, but I've always had great luck and almost always get a full box with all the cables, manuals and everything and the components have always worked. If your budget is tight, refurbished items are a great way to go. You may get one that doesn't work, but NewEgg is great about the RMA thing, and you'll have a replacement in less than week (3 days if you do it right).
What you have is a computer that will eat the Celeron for dinner and it's done for $131, total. Better motherboard, too. The cost of shipping that Tiger Direct would have charged you would make it a wash. If you can dig up $20 more, get the retail packaged Athlon XP 2500+ Barton ($92).
The hard drive will work, but like the earlier poster said, it'll be a bottleneck. Hope this helps. Just sounded like you were on a really tight budget.
-Brett