I bought an MSI Wind U130 Netbook last September.
Shortly afterwards I installed a RAM upgrade chip to improve the speed of the machine.
I checked with the manufacturer (MSI) about the upgrade as you have to break the warranty seal to get into the machine. They said that it was fine to upgrade the RAM as long as no other damage was done and it would not invalidate the Warranty.
Everything was fine with it and I was very pleased with the netbook.
Last week a fault occurred with the display.
With Argos clearance laptop returns are with d&j Henry. When I phoned them to arrange a repair I asked them if I should remove the extra Ram chip before I sent it back, and they said as I had broken the warranty label the warranty was now invalid! They would not budge even though I told the them manufacturer had OK'd the upgrade.
I phoned argos clearance about it and they said the warranty was voided also.
So buyer beware don't open the back to upgrade or the warranty is voided.