Lightroom :: Images Not Showing In Library Mode After Import

Our problem with Lightroom is this: After inporting images, they do not show in the library mode. The tree view shows first image of the folder, but the library preview does not open.- Probllem is persistant and any new images after 3 weeks are not showing up.- problem is resistant, we upgraded from 5.0 to 5.3, but problem is consistant.
 
System specs: Generic computer, 8gb memory, windows 7 ultimate 64bits.c: (SSD) houses lightroom, windows & catalogue files.d: houses inport with Picasa files.p: Container of accepted and to be edited image f
 
General process of images: Import with picasa of images, verification of image quality and rejecting failures.After all images are done, use of syncredibles program to copy new files not yet on the picasa library folder. This basicly checks and moves pictures that are currently on drive D: but are not yet on drive P. After new files are transferred, then picasa will re-import with add function on import from its own folders.
 
Directory structure: c:program files adobelightroom 5.3  (main proigram)c:uusi kansiolightroom caltalogued:kuvat (picasa image store)
p:kuvat (lightroom image store)
 
The divasion of d: and P: driwe is so that picasa will not see images that arte on Lightroom and vice versa.are on D: & P started to get "read obn
 
We have tried to study this problem, and first we notised that folders that houses images on both driwes, started to receve "read only" atrribute. Even tho we cleared this with user restrictions (folder security) the imported images still refuse to load the previews.Catalogue contains over 30 000 raw images.
 
We are starting to shoot blanks here. In short, the tree view shows first image of the folder, images are present in the system, but when you click the tree view to open up the folder, no images will refresh to center view of the screen. If pressed couple of times screen will go white, and crash LR.We have tried to "find missing files" and "folder synchronication.