a crt screen is large, heavy and cumbersome (the largest crt screen manufactured is 42 inch and weighs 142 kg).

How would the previous sentence be correctly capitalized?
Answer: A CRT screen is large, heavy and cumbersome (the largest CRT screen manufactured is 42 inch and weighs 142 kg).
sppnp.dll missing / not found error: unavoidably pc may get infected by virus like trojanspy:win32/bancos.ib or controlled by malware like proactive password auditor. after they are removed by antivirus such as comodo antivirus, the infected file sppnp.dll would be deleted as well so that missing problem is found.

How would the previous sentence be correctly capitalized?
Answer: sppnp.dll missing / not found error: Unavoidably PC may get infected by virus like TrojanSpy:Win32/Bancos.IB or controlled by malware like Proactive Password Auditor. After they are removed by antivirus such as Comodo Antivirus, the infected file sppnp.dll would be deleted as well so that missing problem is found.
product descriptions and specifications are based on information sites of manufacturers. scope of delivery, performance and appearance of samsung sc4140 vacuum cleaner may be subject to change without notice.

How would the previous sentence be correctly capitalized?
Answer: Product descriptions and specifications are based on information sites of manufacturers. Scope of delivery, performance and appearance of Samsung SC4140 vacuum cleaner may be subject to change without notice.
unsure about which type of nch file you have? do you want to know exactly what it is, who created it, and how to open it?

How would the previous sentence be correctly capitalized?
Answer: Unsure about which type of NCH file you have? Do you want to know exactly what it is, who created it, and how to open it?