Maintain Top Performance
If you want to keep your system fast, clear out your C:\Windows\Temp folder on occasion. Do it as soon as you boot into the OS, or even through Safe Mode, to ensure that you wipe every last unused file from your drive. In the same vein, don't use Windows 7's uninstall function or a program's default uninstall executable to remove an application from your drive. Instead, use the free Revo Uninstaller utility; this awesome application removes programs using their default uninstall routines, but it also goes one step further by scanning your system and Registry to clean away all traces of the program from your hard drive.
Accelerate Your Network
Network slowdowns can be tricky to troubleshoot. Much depends on what you're actually doing across your network--copying files to another system, for example, might slow to a crawl if you're writing to a NAS device attached to a poky PC in the next room. But a few general tweaks and tricks can still boost your network performance in Windows.
Update Firmware and Drivers
The first step in getting your network up to speed is to install the latest Windows updates and to download the newest drivers for your PC's network cards. Second, install the current firmware for your router. All of these items are essential to optimal network speeds, and you can usually locate them on the manufacturer's Web sites. If the release date for a given driver is more recent than the last time you can remember updating, you should probably update again. Most new routers make updating easy if you log in to the Web administration panel; typically it will have an option for you to download and install the latest firmware with just a click or two.
Adjust Network Card Settings
Once you have the latest software and firmware installed, try adjusting your network card's auto-negotiating setting. In the Control Panel, click Network and Sharing Center. From there, click Change Adapter Settings, and then right-click on your Local Area Connection and select Properties. In the screen that appears, click the Configure button under the Connect Using field. Select the Advanced tab. Set 'Link Speed & Duplex' to its highest available setting, such as 100 Mbps Full Duplex or 1000 Mbps Full Duplex.
Make Windows Set You Free
Windows Vista has a wonderful habit of throttling down your network connection when you're playing multimedia files, to prevent movies from skipping during playback. You can adjust this throttling by editing the decimal value of the 'NetworkThrottlingIndex' key.
Press Windows-R, type regedit, and press Enter. In the Registry Editor, navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile key. Raise the decimal value of the 'NetworkThrottlingIndex' key to a higher number. Setting it to 100 disables the service; Microsoft recommends that you go no higher than 70, but there's no harm in testing settings to see what works for you.