Running with a cold slow you down/make you feel too heavy to run?

Your training is probably wearing you down and you may even be overtraining. Yes, this is due to you having a cold. If the event is still a few weeks away, it's okay to take a few days entirely off and just get good nutrition (including protein for your immune system) and let your body rest and heal. You normally shouldn't train if you risk pulling something into your chest, or if it's already in your chest. And if you have a fever, your body isn't going to be regulating your temperature correctly, either. You'd normally need to take a full two weeks off to start noticing a significant fitness drop. Your biggest risk is going to be pushing too hard too soon and wearing your immune system down and/or making the cold worse. I'd seriously just rest and heal up. Give yourself 3-4 days of rest. Recovering correctly is half your training, and if you're trying to do 10+ miles with a cold you're being foolish.

I would say you first of all scan your system with any good system cleaner such as Reginout to clean your system of excessive data that gives errors and cause slowdown. Also, uninstall unnecessary programs. I hope your problem will be solved. Few more steps will also help you: 1. Make Sure Your Hardware is Sufficient: Above and beyond everything you can do with software to optimize the function of your computer, making sure you have the proper hardware to support Windows is critical. 2. Clean Your Desktop: Is your Windows Desktop dotted with files? Have you noticed that your computer has been running slower and slower? Do you see the hard drive light often flashing while you wait for the computer to respond to an action? There are steps you can take to fix it. Read this article. 3. Scan Your Windows System for Errors: An operating system is a collection of files that perform different functions. It is possible, over time, that one or more of these system files has changed or become corrupted. If this happens, the speed of your system may decrease. By using a utility called “System File Checking”, it will inspect these files and correct any problem it finds. 4. Scan for Viruses, Spyware and Adware: Every Windows computer is vulnerable to viruses. Viruses are nasty little programs that cause both major and minor problems for users. Spyware and Adware are programs created by companies to find out more information about customers, so they can better market products to them. Spyware and Adware can load into computer memory and slow it down.Periodically scanning and removal of Viruses, Spyware and Adware is a great way to improve computer performance. 5. Uninstall Unused Programs: Over time, you may have accumulated programs on your computer that you do not use. When a program is installed, it creates connections between the program and the operating system. Even if you don’t use these programs, they can slow down your system. If you have the original program’s installation disk or file, removing programs will free up space on your computer and may speed up your system's performance. 6. Adjust Visual Effects for Better Performance: Windows provides a number of interesting visual effects including animated windows and fading menus. If you do not have enough operating memory (see above number 1), these effects can slow down your computer. Adjusting or reducing visual effects can make a difference. 7. Don’t Automatically Start Programs: Programs use operating memory (RAM, also called system resources). Unless you always use these programs, you can keep them from loading at Windows startup and speed both the booting of your computer and its performance. Manage startup programs using reginout. 8. Defragment Your Hard Drive: The more information and programs you have on your computer, the more it is likely that Windows has placed parts of the same file in different locations on your hard drive. It may do this for hundreds of files and programs, depending on how much space is available. Defragmenting the hard drive places all information for each file in one place. The result can be a faster computer experience.