According to Lenovo's website, T400 series max RAM is 4GB (the T500 lists maximum RAM at 8 GB). You did not specify the exact model, maybe your laptop is different. Also, the website only lists dual core CPUs for that PC, and the highest CPU listed is an Intel Core 2 Duo processor T9800. So you would need to spend about $15 to $20 to get an additional 1 GB of RAM (buying a 2GB module to replac, and about $50 to $65 to get the fastest CPU. That is assuming you can do the swap yourself. It will cost more if you have someone else do it. Not to mention if your OS is 32 Bit, you would need to get a 64 Bit version to take advantage of the additional 1 GB of RAM. It does not sound cost effective for the few percentage points in performance gains, But I am not your accountant. A larger hard drive will not boost performance unless you are nearing 80% capacity. Add it all up: $20 for RAM, $65 for CPU, $80 for new OS, $35 for a 320 GB drive (you are not limited to capacity of the drive, you can get a 1 TB if you want) it comes out to around $200. Considering the laptop may be worth around $140 at most, I'll let you decide.