First try reseating both ends of the LVDS cable.
By "reseating" that basically means unplugging, and re-plugging them in their slots right?
fixed a few monitors similar to that by replacing a few bad caps. Look for swollen caps. Sometimes the tops of them will have a bulge or a split. It might be better to just replace them all.
Look on the Power supply board for Bad Capacitors they will be vented or puffed up on Top.
This board will be on the Far Left hand side,pull it out and look for bad Caps.
You need to know how to Solder with an solder Iron, unsolder bad caps and replace with new .
Make sure you put them back in the exact same way the came out,they will be marked postive side and Negative - Side. If they are 1,000uf 16v make sure the cap is 1,000uf. If you want to just replace the board,please contact an expert for help.
It can be a like dead pixels too. How many dots do you see? Some companies have a policies where they state a certain number of dead pixels is "normal" and a limitation/product of the technology. So, I'd say the store is the best place to go to in terms of getting any sort of return/service. Again, it differs company-to-company, and I can't say what Hitachi's policy is.
Bottom line is that it's probably dead pixels. So, it's not something you should have to deal with. Especially if it's multiple.
Also you might be a panel or board defect that will progressively get worse. You would have to take it to a tv show when it gets worse, have them diagnose the problem, then either replace the board ($400 bucks most likely) or the panel which is equally as expensive.
Hope it helped..
Please keep me posted.